Pretty neat💯

For the operations scaffolding, I would personally prefer avoiding scaffolding everything in WeightedOperations and trying to perform file creation as much as possible. Keeping file modification only to append element in list, so in this case, appending the operation method in the returned list []simtypes.WeightedOperation like spn:

return []simtypes.WeightedOperation{
		simulation.NewWeightedOperation(
			weightMsgCreateChain,
			launchsimulation.SimulateMsgCreateChain(am.accountKeeper, am.bankKeeper, am.keeper),
		),
		simulation.NewWeightedOperation(
			weightMsgEditChain,
			launchsimulation.SimulateMsgEditChain(am.accountKeeper, am.bankKeeper, am.keeper),
		),
		simulation.NewWeightedOperation(
			weightMsgRequestAddGenesisAccount,
			launchsimulation.SimulateMsgRequestAddGenesisAccount(am.accountKeeper, am.bankKeeper, am.keeper),
		),
                // ...
	}

I would suggest having the template:

func (am AppModule) WeightedOperations(simState module.SimulationState) []simtypes.WeightedOperation {
	operations := make([]simtypes.WeightedOperation, 0)

	// ...

	// placeholder for simState.AppParams.GetOrGenerate

        return []simtypes.WeightedOperation{
		// placeholder for operation
	}
}

And scaffolding the operation in x/{module_name}/simulation/{message_name} or x/{module_name}/simulation/{type_name}

I got this error when runnnig the simulation: invalid memory address or nil pointer dereference

I think it would be fine to return an empty operation with simtypes.NoOpMsg for scaffolded types and messages

If I run commands from the PR's description, it returns the following (see the gist). Is this the expected result?

https://gist.github.com/fadeev/68c1abff3b7912bf8ce9f7c785d4910e

@fadeev and @lubtd, the reason is an issue with the bank and the account module for simulations. It's fixed. You can try now.